PROJECT SUMMARY Carcinogenesis involves the dysregulation, both mutational and transcriptional, of the complex interactions of hundreds of genes. Currently no platform allows for the predictable transcriptional modulation of this many genes simultaneously. Gene transcription is modulated by a number of mechanisms including the well-studied histone modification and genome compartmentalization mechanisms as well as the still insufficiently understood role of the complex physical nanoenvironment within chromatin. Since transcriptional molecular interactions are chemical reactions, they depend on the local physical environment within the chromatin which, in turn, depends on the physical pattern of chromatin folding at supra-nucleosomal length scales. The overarching goal of this project is to develop new tools to modulate the chromatin nanoenvironment for whole- scale transcriptional engineering for cancer prevention and therapeutics. Transcriptional diversity plays a major role in carcinogenesis by allowing cancer cells to explore their genomic space and has been shown to foster the emergence of resistance to chemotherapy in cancer cells. The project will leverage the methods of bioengineering to develop new tools to physico-chemically regulate chromatin structure toward a normalized, constrained, and less-adaptive state. The project will identify physico-chemical mechanisms that can be targeted to reduce transcriptional heterogeneity and validate the efficacy of the chromatin folding-normalization in patient- derived xenograft (PDX) tumor models of colon cancer as an adjuvant therapy for alleviating chemoresistance through the reduction of the transcriptional heterogeneity of tumors.